Neuropsychological improvement in patients with cervical spondylotic myelopathy after posterior decompression surgery

Patients with cervical spondylotic myelopathy sometimes complain of cognitive dysfunction, which may be coincidence. However, cognitive dysfunction may be related to disorders of the cervical spine and/or spinal cord. This study investigated cognitive dysfunction in patients with cervical spinal disorders. A total of 79 patients with cervical spondylotic myelopathy (40 women and 39 men, mean age 61.2 years) underwent cervical laminoplasty between January 2006 and July 2007. Ten of these 79 patients (7 women and 3 men, mean age 65.2 years) complained of moderate to severe memory disturbances. These 10 patients underwent neuroimaging studies and a battery of neuropsychological tests consisting of the mini-mental state examination, Kohs Block Design Test, Miyake Memory Test, Benton Visual Retention Test (BVRT), and "kana-hiroi" test before and 3 months after surgery. Brain magnetic resonance imaging showed no organic brain lesions in the 10 patients, but single photon emission computed tomography demonstrated reduced regional cerebral blood flow in the posterior cortical areas in eight patients before surgery. Neuropsychological test scores showed statistically significant improvement after surgery in the Kohs Block Design Test and the BVRT, which measure visuospatial perception and reflect the function of the parietal and/or occipital lobes (p < 0.05). The practice effect may have contributed to the neuropsychological improvements, but this study suggests that cervical spinal disorders may affect cognitive functions and that surgical treatment can ameliorate such effects.